ProjectSummary/Abstract: Uncontrolleddiabetesandinsulinresistanceleadstoenergyimbalance,disruptedproteinturnoverand mitochondrialdysfunction,especiallyinskeletalmuscle.Thesechangescanleadtoacceleratedlossof strengthandmusclewastingwhichincreasestheriskofmorbidityandmortalityinolderindividuals.The signalsthatcontrolmitochondrialmetabolisminmuscleduringdiabetesremainincompletelyunderstood.I havedemonstratedthatinsulinandIGF-1controlmuscleproteinturnovertomaintainmusclemass,andthat thiscontrolisdependentonFoxOtranscriptionfactors.Furthermore,preliminarystudiesshowthatinsulin- deficientdiabetesleadstomusclewastingthroughcellularautophagy,or?selfeating?,thatcanbeprevented bydeletionofFoxOsinmuscle.ThegoalofthisproposalistoinvestigatewhetherFoxOproteinscontrol musclemitochondrialmetabolismandmitochondrial-specificautophagy,or?mitophagy?inthecontextof diabetes.However,aquantitativemethodtomeasuremitophagyinmuscleisnotcurrentlyavailable.To accomplishthegoalsofthisprojectIwill(a)measuremusclemitochondrialrespirationinmicewithmuscle- specificdeletionofFoxOisoforms(FoxOTKO)thatarerendereddiabeticusingstreptozotocinandcorrelate thiswithmeasuresofmitophagyincellslackingFoxOs,and(b)developaquantitativemethodtomeasure mitophagyinmuscletissueusingproximityligationassaycoupledtorollingcircleamplification(PLA/RCA). Mylong-termgoalsaretounderstandtheimpactofdiabetesandinsulinresistanceonproteinturnovertogain insightsintothemetabolicandmitochondrialchangesthatcanimpactcomplicationsofthisdisease.